The invention relates to a tripod joint with an outer joint component having three circumferentially distributed recesses with parallel axes, forming circumferentially opposing tracks. An inner joint component having a spider-shape in cross-section with three circumferentially distributed arms engages the recesses of the outer joint component. Roller assemblies are supported on the arms. Each roller assembly includes a roller-carrying means and a roller running directly on the tracks. The rollers are arranged to slide axially to the arm axis and free to angularly pivot relative to the arm axis. Also support means are provided between the roller assembly and the outer joint component. The support means absorbs tilting moments exerted on the roller assembly about axes parallel to the joint axis and perpendicular to, and spaced from, the joint axis.
DE 28 31 044, DE 39 36 601 and DE 37 16 962 illustrate various types of tripod joints. Of the first two mentioned, each has the roller supported via a needle bearing on a roller carrier and free to rotate with the roller carrier arranged to slide axially on the arm and to swivel relative to the arm axis. For the first type, the movement is accomplished by an inner race which, with its spherical exterior, engages an at least partially spherical interior surface of the roller carrier. The inner race interior surface is cylindrical and is supported on a cylindrical arm.
In the second case, the roller carrier has an internally cylindrical opening in which an arm with a partially spherical head is engaged for radially sliding and swiveling movement.
The third version has, instead of a roller carrier, an interior roller with a spherical outer surface, which is directly supported and free to rotate on a cylindrical arm via a needle bearing. This interior roller engages an internally cylindrical cavity of the roller and is arranged to slide axially and swivel relative to the arm.
The generic term "elements of the roller assembly" refers to a roller carrier or an interior roller and a roller, where the two roller carriers of the first two joint types can be considered nonrotating elements of the roller assembly. In the following, "roller-carrying means" shall apply to all components of the "roller assembly" with the exception of the "roller".
In an articulated rotating joint, with reference to the interior joint component, radially oscillating movements of the rollers are generated relative to the joint axis as well as swiveling movements of the rollers on their arms and, simultaneously, with reference to the external joint component, longitudinally oscillating roller movements of the rollers are generated along the tracks. The first-mentioned radial and swivel movements are subject to friction while the second-mentioned roller movements predominantly occur as a rolling motion. Due to the frictional forces, with increasing articulation angles, all known tripod joints experience an increasing joint excitation force, e.g., the alternating forces originating in the joint are transmitted to the drive train. If in the course of the motion sequence of a rotating articulated joint, one of the arms, relative to the particular roller and with reference to the outer joint component, relocates toward the inside, and the roller requires radially inward support against the outer joint component, frictional forces are particularly high and detrimental. This is particularly true for support forces generated by tilting moments exerted on the roller assemblies about any axis tangential to the circumference.